The Ubuntu font includes Latin, Greek, and Cyrillic glyphs. The website says Arabic and Hebrew are TBA. Then you have other glyphs such as Thai, not to mention CJK. You're assuming 10ppl/$100k, but the company also needs to make a profit. The font work is usually done in phases, obviously delivering base Latin first and other glyphs/weights are added later. I can't speak to how detailed the hinting is in the Ubuntu font, but that requires lots of tedious work if you need to be able to display/render the font at very small font sizes.

edit: Wikipedia also contains this regarding Dalton Maag, the foundry which created the Ubuntu font:

"In July 2012 the Rio 2016 Olympic Games released their brand font created by Dalton Maag. It was based on the letters and numbers within the logo already created by Brazilian design agency, Tátil.[11] The typeface took eight months to create and comprises 5448 characters. The design work was mainly done by Dalton Maag’s Brazilian office, which worked with the London team during the font engineering stage, and also with Brazilian consultant Gustavo Soares, who worked as the technical interface between Dalton Maag and the Rio 2016 team."

There's an example of a typeface built over 8 months using two teams in two countries.